Condensed Consolidated Statement of Changes in Stockholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock [Member]	Accumulated Other Comprehensive Loss [Member]	Capital in Excess of Par Value [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2012	$ 51,928	$ 131	$ (226,168)	$ 559,970	$ (282,005)
Balance, shares at Dec. 31, 2012		13,140
Stockholders' Equity Line Items
Amortization, issuance and forfeitures of restricted stock grants (in shares)		304
Amortization, issuance and forfeitures of restricted stock grants	1,164	3		1,161
Unrealized gain on available-for-sale investments, net of tax	1,710		1,710
Reclassification of unrealized loss on available-for-sale investments, net of tax	2,362		2,362
Foreign currency translation adjustments	(657)		(657)
Net income	8,015				8,015
Balance at Mar. 31, 2013	$ 64,522	$ 134	$ (222,753)	$ 561,131	$ (273,990)
Balance, shares at Mar. 31, 2013		13,444